Changes: Easily switch between source and header file

Revision as of 08:16, 15 September 2010

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created December 6, 2002 · complexity intermediate · author bubbleboy · version 5.7

Switching between source and header files is a frequent operation, and so many ways to do it have been suggested. This article tries to list them all, and also list their advantages and disadvantages.

Script a.vim

A vim script that does this can be found here: script#31, and is called a.vim.

Pros

Ease of use.
Handles multiple filetypes (not just C and C++), can be easily configured for more.
Code is very well commented.
Works with different extension styles (.C .c .cxx .cpp .CPP, .cc <--> .h .hpp .H .HPP) all at the same time - a switch will work from any source to any header extension and vice-versa.
The path where the associated file must be searched can be configured.

Cons

Quite large (~ 350 lines of code, not counting comments).

Remarks

It was hard to add new filetypes in older versions of the script, but that is no longer the case.

Script FSwitch.vim

Another vim script that does this can be found here: script#2590, and is called FSwitch.vim.

Pros

Essentially same as a.vim
More flexible path definitions for searches
File creation as part of switching is handled well (a sore point with a.vim, apparently)
Smaller code size than a.vim (I'm not sure a.vim's code size was ever relevant though))
Heavily documented
The author is still current and willing to add features and fixes (as of Mar 2009)

Cons

Nothing's perfect.

Using ctags

ctags files can be used to find a file very quickly. Just add the "--extra=+f" option in the ctags line. You may then open new files manually with autocompletion, with :tag myfile.cpp Or you may adapt a script like a.vim or FSwitch.vim to call :tag with the correct filename.

Pros

Very quick

Cons

ctags files need to be generated

By modifying ftplugins

This was the original suggestion for this article.

Pros

Easy to add new filetypes
highly configurable.

Cons

You have to modify filetype plugins (not that bad).
:find can be slow, especially when the file you are switching to does not exist.
Error when file does not exist.

To switch between header and source files very quickly, all you need to do is add a few key mappings in your filetype plugin files. Let me explain with an example:

Let's say that you're editing C files, so all you would have to do is edit your ftplugin/c_extra.vim file and include

nmap ,s :find %:t:r.c<CR>
nmap ,S :sf %:t:r.c<CR>

to switch to the corresponding source file, and

nmap ,h :find %:t:r.h<CR>
nmap ,H :sf %:t:r.h<CR>

to switch to the corresponding header file.

The built-in :find command will search (recursively or not) for the specified file anywhere in your vim 'path' setting. The :sf is short for split-find, meaning that if vim finds your file it will open it in a split window. Simply add the vert keyword before sf if you want a vertical split.

The mappings can (and indeed, should) be made local to buffer with a <buffer> modifier.

You may also want to use this function that lets you to only use one binding for switching:

function! SwitchSourceHeader()
  "update!
  if (expand ("%:e") == "cpp")
    find %:t:r.h
  else
    find %:t:r.cpp
  endif
endfunction

nmap ,s :call SwitchSourceHeader()<CR>

See these help pages for a full description of these built-in features:

:help expand() for a description of the %, :t, :r, :e expansion
:help :find for a description of the 'find' and 'sf' features
:help ftplugin for a description of how filetype plugins work
:help 'path' for a description of how the path setting works

This method is also highly configurable. All you have to do is change the 'path' setting when switching to different projects, and modify the corresponding filetype plugin to support other languages.

Because this method uses :find, it may be useful to add file paths to your Vim path automatically when you edit them.

Single line solution

Pros

Only takes one line in .vimrc, and so is very quick to set up

Cons

Only works if the header and source are in the same directory
Does not handle multiple extension styles simultaneously

For programmers that want to switch from foo.cpp to foo.h (or vice versa) on a single key stroke, this might help:

map <F4> :e %:p:s,.h$,.X123X,:s,.cpp$,.h,:s,.X123X$,.cpp,<CR>

it maps (on F4) the change of the current filename. The endings ".h" and ".cpp" are exchanged (via the magic ending ".X123X").

You could use ".hpp" or ".c" filename endings by changing it in the replacement statements.

For more explanation on how this function operates, see :help filename-modifiers.

A short function

Pros

Still short enough to put into vimrc.

Cons

:find can be slow.
overwrites path

Put these lines in ~/.vimrc and F2 will flip between .c and .h, .hxx and .cxx, etc. Moreover the .h file need not be in the same dir, it can be found via path variable.

set path=.,,..,../..,./*,./*/*,../*,~/,~/**,/usr/include/*

function! Mosh_Flip_Ext()
  " Switch editing between .c* and .h* files (and more).
  " Since .h file can be in a different dir, call find.
  if match(expand("%"),'\.c') > 0
    let s:flipname = substitute(expand("%"),'\.c\(.*\)','.h\1',"")
    exe ":find " s:flipname
  elseif match(expand("%"),"\\.h") > 0
    let s:flipname = substitute(expand("%"),'\.h\(.*\)','.c\1',"")
    exe ":sp " s:flipname
  endif
endfun

map <F2> :call Mosh_Flip_Ext()<CR>

You can save your place when you switching back and forth by checking the buffers before opening the file.

function! CocoaMondo_LoadFile(filename)
  let s:bufname = bufname(a:filename)
  if (strlen(s:bufname)) > 0
    exe ":buffer" s:bufname
  else
    exe ":find " a:filename
  endif
endfun

Manual switching

Pro: No need af changing anything - works with every VIM

Con: A little more work to use than a full-featured script that "just works"

A simple way to manually switch between headers and sources is by using the %< built-in variable, that resolves to the file name without extension. To switch from a header to a source you can do:

 :e %<.c

Or:

 :split %<.c

if you want to open it in a new "window".

Comments

The Single line solution can also easily be made to split the window horizontally:

 map <F4> :sp %:p:s,.h$,.X123X,:s,.cpp$,.h,:s,.X123X$,.cpp,<CR>

or vertically:

 map <F4> :vs %:p:s,.h$,.X123X,:s,.cpp$,.h,:s,.X123X$,.cpp,<CR>

Sometimes this works

If the file begins by including the header file like this:

 #include "somefile.h"
 ...

go there with "ggW" and tell vim to open it with "gf" (go back with "CTRL_o"). Add "set path=.,<relative include dir>" for searching for header in particular directories. For more information do ":help file-searching".

Bonus Typing "CRTL-W s" in advance shows you both the original file and its header file

Pro: No need af changing anything - works with every vim

Con: Doesn't work backwards (from file.h to file.cpp)